夏季木槿上棉蚜的种群动态及其寄主利用能力

 【目的】阐明南京地区冬寄主木槿上棉蚜种群年生活史的分化。【方法】采用定点、定株、定枝的系统调查及寄主转接建立生命表方法，比较夏季木槿上滞留棉蚜及棉花上棉蚜在主要夏寄主植物上的存活与繁殖能力。【结果】2006年和2007年的整个夏季，棉蚜的冬寄主木槿上均有滞留棉蚜种群存在，并且这些滞留棉蚜均以无翅型为主。木槿上夏季滞留棉蚜不能直接在黄瓜、香瓜、西葫芦、南瓜、四季豆和西红柿等寄主上繁殖后代和建立种群，仅极少部分个体可在棉花和豇豆上发育到成蚜并产仔，但产仔量极低，净增殖率多小于1。但是，滞留棉蚜经棉花寄主饲养多代后，能较好地利用棉花和南瓜寄主，表现出滞留棉蚜仍保持着对一些夏寄主的利用能力。【结论】南京地区冬寄主木槿上的棉蚜种群存在年生活史的多样性，同种群内存在异寄主生活史和同寄主生活史共存的现象;在木槿上营同寄主生活史的棉蚜已经失去或降低了对一些夏寄主的利用能力;棉蚜种群的转寄主生活史特性具有可塑性。

Population Dynamics of Aphis gossypii Glover on Hibiscus Tree in Summer and Its Capacity to Utilize Other Host-plants

【Objective】 The research was to clarify the differentiation in the life-cycle of cotton aphid (Aphis gossypii Glover) on an overwintering host plant, Hibiscus syriacus L. in Nanjing, Jiangsu province, China. 【Method】 The cotton aphids on hibiscus trees were investigated by systematic observation method in a whole summer season. Survival and reproduction of cotton aphids from hibiscus tree and cotton were compared on different summer host-plants using host transplantation and life-table methods. 【Result】 There was a sedentary population of cotton aphid on the overwintering host-plant, hibiscus tree, in the whole summer of 2006 and 2007, and it was mainly apterous. The sedentary cotton aphids from hibiscus trees could not produce offspring and establish population when they were transferred directly to cucumber, muskmelon, zucchini, pumpkin, kidney bean and tomato. Although a minority of the sedentary aphid individuals from hibiscus could grow up into adults on cotton and cowpea, they produced fewer offspring and their net reproductive rate (R0) was less than one. However, the sedentary cotton aphids from hibiscus trees showed better fitness on cotton and zucchini after they were reared on the cotton for some generations. The sedentary aphids on summer hibiscus still kept the capacity to utilize some summer host-plants. 【Conclusion】 The diversity of life-cycle exists in the cotton aphid population on an overwintering host-plant, hibiscus in Nanjing, and the autoecious (host-specific) and heteroecious (host-alternating) coexist in the same population. The aphids, which life-cycle is host-specific on hibiscus, have lost or weakened the capacity to utilize some summer host-plants. The life-cycle of cotton aphid population on overwintering host-plant is flexible.